Obstructive sleep apnea syndrome (OSAS) is part of a metabolic syndrome, whose main aspects are obesity, hypertension and diabetes, already incriminated for cardiovascular events. The evaluation of the effect of OSAS on the hormonal profile of patients shows a number of complex interactions that preclude the exact role of this syndrome among the numerous derangements on hormone levels as well as the effect of continuous positive airway pressure treatment, since many of the changes are known to occur with obesity as well. The clarification of the exact role and the mechanisms underlying these changes will help to stratify the cardiovascular and other health risks of this syndrome as well as the better application of CPAP therapy.